Actuator

Abstract

To provide an actuator which is easily made a small size and flexible, and has a large displacement. The actuator comprises a rod-shaped actuator element, having one axial end thereof fixed, including a dielectric film made of a dielectric elastomer and a plurality of electrodes arranged via the dielectric film, in the actuator element, the dielectric film extends as a voltage applied across the electrodes becomes large, and a load member connected to the other axial end of the actuator element and fixed in a state in which the actuator element is permitted to be extended axially, characterized in that making large the voltage applied across the electrodes causes the dielectric film to be extended, whereby the actuator element is extended axially according to the tension of the load member.

1 . An actuator comprising:
 a rod-shaped actuator element, having one axial end thereof fixed, including a dielectric film made of a dielectric elastomer and a plurality of electrodes arranged via said dielectric film, in said actuator element, said dielectric film extends as a voltage applied across said electrodes becomes large; and   a load member connected to the other axial end of said actuator element and fixed in a state in which said actuator element is permitted to be extended axially; characterized in that making large the voltage applied across said electrodes causes said dielectric film to be extended, whereby said actuator element is extended axially according to the tension of said load member.   
   
   
       2 . An actuator according to  claim 1 , wherein said load member is at least one of a weight and an elastic member. 
   
   
       3 . An actuator according to  claim 1 , wherein said load member is said actuator element. 
   
   
       4 . An actuator according to  claim 1 , wherein said actuator element has a spiral extensible member formed by winding spirally an extensible film which includes said dielectric film, a pair of said electrodes arranged on both the surfaces of said dielectric film, and an insulation film arranged on one of the surfaces of a pair of said electrodes. 
   
   
       5 . An actuator according to  claim 1 , wherein said actuator element has a laminated extensible member formed by laminating alternately said dielectric film and said electrodes in concentric circular shape. 
   
   
       6 . An actuator according to  claim 5 , wherein said laminated extensible member has a hollow cylindrical shape. 
   
   
       7 . An actuator according to  claim 1 , wherein said actuator element has a core material which is arranged to an axis portion thereof and is elastically deformable axially. 
   
   
       8 . An actuator according to  claim 7 , wherein said core material is made of an elastomer. 
   
   
       9 . An actuator according to  claim 7 , wherein said actuator element has a spiral tube member formed by winding spirally around said core material an extensible film which includes said dielectric film, a pair of said electrodes arranged on both the surfaces of said dielectric film, and an insulation film arranged on one of the surfaces of a pair of said electrodes. 
   
   
       10 . An actuator according to  claim 7 , wherein said actuator element has a laminated tube member formed by laminating alternately around said core material said dielectric film and said electrodes in concentric circular shape. 
   
   
       11 . An actuator according to  claim 1 , wherein said actuator element has a maximum diameter of less than 5 mm in a direction perpendicular to the axis. 
   
   
       12 . An actuator according to  claim 1 , wherein a plurality of said actuator elements are bound and arranged. 
   
   
       13 . An actuator according to  claim 12 , wherein at least one of a positive pole side and a negative pole side of a plurality of said electrodes of said bound actuator elements is shared in use. 
   
   
       14 . An actuator according to  claim 1 , wherein said electrodes are made of a mixed material comprised of an elastomer and conductive material. 
   
   
       15 . An actuator according to  claim 1 , wherein said electrodes are liquid.